Wire rebar chair

ABSTRACT

A unitary wire chair is disclosed for supporting concrete reinforcing rebar or the like above a supporting surface onto which concrete is poured. The unitary wire chair is so constructed such that it may be snapped or otherwise secured onto the rebar or other concrete reinforcing element and retained thereon without the use of any tie wire or other attachment devices.

TECHNICAL FIELD

The present invention relates to spacers, or so-called chairs, that areused in construction for the support of rebar, post-tension cables orwire mesh. More particularly, the present invention relates to chairsmade of wire that are used for the support of rebar, post-tensioncables, or wire mesh in poured concrete.

BACKGROUND OF THE INVENTION

Spacers, or so-called chairs, are commonly used in the concreteconstruction industry for the support of rebar or post-tension cables ormesh above a surface onto which concrete is to be poured. Typically,rebar, cable or mesh, when used to reinforce concrete, must be supportedabove the surface onto which the concrete is poured. Chairs aregenerally used with poured concrete decks, pre-cast work, and bridges,roads or so-called slab-on-grade applications. In use, a rebarsupporting surface on the chair supports the rebar while the base of thechair rests on the deck or surface to which the concrete is to beapplied. When the concrete is poured, the chair maintains the cable orrebar a proper distance above the supporting surface.

Currently, one of the most popular chairs used to support rebar is madefrom a pair of bent wires. A first bent wire is generally in the shapeof an inverted U and has a recessed surface in the cross bar at the toponto which the rebar is located. The sides of the U-shaped wire supportthe recessed cross bar in an upright condition above the supportingsurface. A second wire is formed as an inverted U and is welded to thebottom edge of the cross bar of the first wire and extends at 90° tothat cross bar. The second wire also has vertically extending legs whichsupport the second wire above the supporting surface. Generally, toprevent the rebar supported from this type of wire chair during pouringof the concrete, the rebar is tied to the supporting surface of thechair by a tie wire.

One problem with this type of wire chair is that it is relativelyexpensive to manufacture because of the welding required in the courseof its manufacture, but also because it requires substantial hand laborto manually attach the rebar to the chair by means of tie wires. It hastherefore been an objective of this invention to provide a wire chairwhich is less costly to manufacture and which eliminates the need fortie wires to attach the wire chair to the rebar.

There have been rebar supporting chairs manufactured which do notrequire the use of tie wires for attachment of the chair to the rebar.For example, as disclosed in U.S. Pat. No. 5,893,252, there are chairswhich may be snap-fit onto the rebar so as to support that rebar above asupporting surface, but such snap-on-type of rebar supporting chairshave generally been made of plastic and are substantially more expensiveand difficult to manufacture than wire rebar supporting chairs. It hastherefore been another objective of this invention to provide a wirerebar supporting chair which may be snapped onto a rebar andfrictionally held thereon without the need for tie wires or a complexplastic snap-fit connection.

SUMMARY OF THE INVENTION

The wire rebar chairs of this invention are formed from a single unitarywire which supports a concrete reinforcing rebar or the like and whichare so constructed that they may be snapped onto or otherwise securedonto the rebar or other concrete reinforcing element and retainedthereon without the use of tie wires or other attachment devices. Tothat end, one embodiment of the invention comprises three parallel crossbars, a central one of which is adapted to be received atop a rebar andthe other two parallel cross bars of which are adapted to be received onthe underside of the rebar with connecting bars connected to oppositeends of the central one of the three parallel cross bars and riser barsextending downwardly away from the ends of each of the other twoparallel cross bars, which riser bars terminate in a supporting foot.The supporting foot is intended to rest upon the supporting surfacewhile concrete is poured onto that supporting surface. Preferably, thiswire chair is heat-treated after formation of the chair so as to impartspring-like qualities to the wire chair, such that when secured onto arebar, the spring-like qualities retain the wire chair on the rebaragainst any forces which it might otherwise tend to displace it.

Another embodiment of the invention comprises a single unitary wireformed as two riser bars extending upwardly from opposite ends of asupport foot section of wire. The two upwardly extending riser barsterminate in generally U-shaped loops which snap over and onto oppositesides of a rebar or like concrete reinforcing wire.

In yet another embodiment of the invention, a single unitary wire has astraight upper horizontal bar section from the opposite ends of whichare formed generally U-shaped loops which snap over a rebar orrebar-like concrete reinforcing wire. At the end of the loops oppositethe straight horizontal bar section, riser bars extend generallydownwardly to supporting foot sections of wire.

As a still further modification of the embodiment described immediatelyhereinabove, the generally U-shaped loops are connected to a generallyV-shaped nose section of the chair wire rather than a straight upper barsection of the unitary wire.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other variations and embodiments of this invention will bemore readily apparent from the following description of the drawings, inwhich:

FIG. 1 is a perspective view of one embodiment of the wire chair of thisinvention supporting a rebar shown in phantom;

FIG. 2 is a perspective view of multiple chairs supporting a rebar abovea supporting surface;

FIG. 3 is a side elevational view of the wire chair of FIG. 1 supportinga rebar;

FIG. 4 is a top plan view of the wire chair of FIG. 1, the rebar beingshown in phantom;

FIG. 5 is a perspective view illustrating how the wire chair of FIGS.1-4 is applied to the rebar;

FIG. 6 is a perspective view of a modified form of chair incorporatingthe invention of this application; and

FIGS. 7, 8 and 9 are perspective views of three further embodiments ofthe invention of this application.

DETAILED DESCRIPTION OF THE INVENTION

With reference first to FIG. 1, there is illustrated a concretereinforcing element of rebar 10 and a rebar chair 12 made of one pieceof wire 5 for supporting that rebar 10 a predetermined distance above asupport surface 14 (see FIG. 2). The chair 12 comprises three parallelcross bars 16, 18 and 20, the centermost one, 18, of which is connectedto the other two 16 and 20 via connector bars 22 and 24. As may be seenmost clearly in FIG. 3, the centermost one of these three cross bars 18is located atop the rebar 10 and the two other cross bars 16 and 18 arelocated on the underside of the rebar 10. At its opposite ends, thecentermost cross bar 18 is connected to the cross bars 16 and 20 byconnector bars 22, 24 which extend downwardly and outwardly fromopposite ends of the uppermost cross bar 18. Ninety degree (90°) bends26, 28 in the wire connect the opposite ends of the cross bar 18 to theconnector bars 22 and 24, respectively. See FIG. 4. Similarly, anotherninety degree (90°) bend in the wire 5 connects each of the connectingbars 22, 24 to cross bars 16 and 20, respectively. See FIG. 4.

The ends of the outermost cross bars 16 and 20 opposite the endconnected to the connector bars 22 and 24 is connected via ninety degree(90°) bends 34, 36, respectively, to riser bars 40, 42. The riser bars40, 42 extend downwardly and outwardly away from the cross bars to whichthey are connected and terminate in supporting feet 44, 46. Eachsupporting foot 44, 46 is connected to the lower end of the riser bars40, 42, respectively, by ninety degree (90°) bends 48 and 50, in thewire, respectively. See FIG. 4.

In the embodiment of the invention illustrated in FIGS. 1-4, each of thecross bars 16, 18 and 20, as well as each connector bars 22 and 24, andeach riser bar 40, 42 is a linear straight bar connected to its nextadjacent bar by a ninety degree (90°) bend in the wire 5. Soconstructed, this embodiment of wire chair 12 may be easily formed on aconventional wire bending machine.

As may be seen most clearly in FIG. 3, when the chair 12 is placed overa rebar 10 or other concrete reinforcing element, the cross bars 16, 18and 20, as well as the supporting feet 44 and 46 are all located in ahorizontal plane with the supporting feet 44 and 46 intended to beresting upon the support surface 14 over which concrete is to be pouredto encase the rebar or concrete reinforcing element in the concrete. Inthe embodiment here illustrated, the connecting bars 22 and 24 extenddownwardly and outwardly from the horizontally extending cross bar 18 atan angle a approximately thirty degrees (30°) to a vertical plane 52through the cross bar 18. And in the preferred embodiment, the riserbars 40, 42 extend downwardly and outwardly from the horizontal crossbars 16 and 20 at an angle β at approximately thirty degrees (30°) to avertical plane 54 through the cross bars 16 and 20, respectively.

In order to accommodate the chair to differing applications, the anglesα and β may vary, as well as the length of the riser bars and connectorbars. For example, if a smaller rebar or concrete reinforcing wire orelement is utilized, the connector bars 22 and 24 will be shortenedand/or the angle a increased to as to accommodate the smaller diameterrebar or wire. And similarly, if the rebar or concrete reinforcingelement is to be increased in elevation relative to the supportingsurface 14, the length of the riser bars 40 and 42 would be increasedand/or the angle β decreased to accomplish the increased elevation ofthe supported rebar or reinforcing element.

In one preferred embodiment of this invention, after formation of thechair 12, the chair is preferably subjected to a heat treatment so as toimprove and increase the formed stability of the formed chair. Onesuitable heat treatment involves subjecting the formed chair to atemperature of 450 to 550° F. and then cooling the chair to roomtemperature so as to result in its having spring-like resilientqualities. Not only does this heat treatment increase the forms orshaped stability of the chair, but it better enables the chair to grip arebar 10 inserted into the gaps 56, 58 between the cross bars 16, 18, 20as explained more fully hereinafter.

With reference now to FIG. 5, it will be seen that in order to attach achair 12 to a rebar 10, all that is required is for the chair 12 to bemoved into a position relative to the rebar 10 in which the rebar islocated within one of the pockets or gaps 56, 58. Pocket 56 is definedbetween cross bars 18 and 20. Pocket 58 is defined between cross bars 18and 16. See FIG. 4. Thereafter, the chair 12 may be rotated ninetydegrees (90°) so as to position the rebar 10 within the other of the twopockets 56, 58. See FIG. 5. When so positioned, the centermost cross bar18 is located atop the rebar 10 and the other two cross bars 16 and 20are located on the underside of the rebar 10. Preferably, the connectorbars 22 and 24 are of such a length and the angles a are such that inthe course of rotating the chair ninety degrees (90°) so as to positionthe rebar 10 within the two pockets 56 and 58, the cross bars 16 and 20are forced outwardly away from the centermost cross bar 18 so as tosecurely lock the rebar 10 within these pockets 56, 58.

With reference now to FIG. 6, there is illustrated another embodiment ofthis invention. This embodiment of wire chair 12′ is identical to theembodiment of FIGS. 1-5 except that the connector bars 22′ and 24′ aresemicircular rather than straight bars. There are bending machines whichwill accommodate this configuration of wire bending without the need forninety degree (90°) bends between the cross bars and connecting bars asin the embodiment of FIGS. 1-5.

In the embodiment of FIG. 6, there may be detents (not shown) formed inthe cross bars 18, 16 and 20, respectively, so as to better enable therebar 10 supported by the chair to be locked into the pockets 56, 58 ofthe chair. The detents will assist in preventing the chairs from beinginadvertently knocked off of the rebar in the event that the force ofthe poured concrete contacting the chair tends to dislocate it, or inthe event that workmen working in connection with the rebar step over oron it and tend to displace it.

With reference now to FIG. 7, there is illustrated another embodiment ofa wire chair incorporating the invention of this application. This chair60 comprises a unitary wire, the center portion of which comprises astraight horizontal bar section 62 at the opposite ends of which thereare formed generally U-shaped loops 64, 66 which are so sized as to besnapped over a rebar 68 or similar concrete reinforcing wire or rod.These loops 64, 66 terminate in a generally vertically extending riserbar 70, 72 at the end of each of which there is a horizontal extendingsupporting foot 74, 76. These supporting feet, 74, 76, support the chair60 upon the surface to which concrete is to be applied after the rebaror concrete reinforcing wire or bar 68 is snap-fit into the loops 64, 66of the chair 60.

With reference now to FIG. 8, there is illustrated yet anotherembodiment of a chair incorporating the invention of this application.This chair 80 is very similar to the chair 60 of FIG. 7 except thatinstead of the generally horizontally extending straight bar 62, thegenerally U-shaped loops 84, 86, which are intended to be snap-fit overa rebar 68 or concrete reinforcing wire or rod, are connected to agenerally V-shaped nose piece 82. The opposite ends of this V-shapednose piece 82 terminate in the loops 84, 86 within which the rebar 68 isreceived. The lower ends of these loops 84, 86 are connected to risersections 88, 90 of the chair 80 which in turn are connected tosupporting feet 92, 94. In use, the feet 92, 94 rest upon the supportingsurface to which concrete is to be applied while the chair supports therebar or concrete reinforcing rod or wire above that supporting surface.

With reference now to FIG. 9, there is illustrated yet anotherembodiment of a unitary wire chair incorporating the invention of thisapplication. This chair 100 comprises a generally Z-shaped supportingfoot 102 which forms the center portion of the wire chair. Riser bars104, 106 extend upwardly from opposite ends of this Z-shaped generallysupporting foot 102. These riser bars 104, 106 terminate in generallyU-shaped loops 108, 110 at the upper ends of the riser bars 104, 106,respectively. In use of this chair 100, the rebar 68 or concretereinforcing rod wire 68 is inserted into the loops 108, 110, one ofwhich is located on one side of the rebar or rod, and the other of whichis located on the opposite side. The rebar 68 is snap-fit into theseloops 108, 110, after which the rebar is firmly held by the chair 100against movement or displacement of the chair 100 during pouring of theconcrete.

It will readily be apparent to persons skilled in the art that while wehave described several embodiments of our invention, other changes andmodifications may be made without departing from the spirit of ourinvention. Therefore, we do not intend it to be limited except by thescope of the following appended claims.

1. A unitary wire chair for supporting concrete reinforcing rebar or thelike above a supporting surface while concrete is poured onto thatsupporting surface, which chair comprises: at least three parallel crossbars connected by two connecting bars, a central one of said threeparallel cross bars being adapted to be received atop a rebar and theother two parallel cross bars being adapted to be received on theunderside of said rebar; and riser bars extending downwardly away froman end of each of said other two parallel cross bars.
 2. The unitarywire chair of claim 1 wherein said two connecting bars are connected toopposite ends of said central one of said three parallel cross bars. 3.The unitary wire chair of claim 1 wherein each of said riser bars isconnected at its lower end to a supporting foot.
 4. The unitary wirechair of claim 3 wherein each supporting foot comprises a linear barwhich extends parallel to said three parallel cross bars.
 5. The unitarywire chair of claim 1 wherein said chair is adapted to be secured onto arebar by locating the rebar between two of said three parallel crossbars and then rotating said chair 90° to lock said chair onto saidrebar.
 6. The unitary wire chair of claim 1 wherein said chair issubjected to heat treatment after formation of said chair.
 7. Theunitary wire chair of claim 6 wherein said heat treatment comprisesheating said chair to a temperature of between 450° to 550° F. and thencooling said chair to impart improved form stability to said chair.
 8. Aunitary wire chair for supporting a concrete reinforcement element abovea supporting surface while concrete is poured onto that supportingsurface, which chair comprises: at least three parallel cross barsconnected by two connecting bars, a central one of said three parallelcross bars being adapted to be received atop a reinforcement element andthe other two parallel cross bars being adapted to be received on theunderside of said reinforcement element; and riser bars extendingdownwardly away from an end of each of said other two parallel crossbars.
 9. The unitary wire chair of claim 8 wherein said two connectingbars are connected to opposite ends of said central one of said threeparallel cross bars.
 10. The unitary wire chair of claim 8 wherein eachof said riser bars is connected at its lower end to a supporting foot.11. The unitary wire chair of claim 10 wherein each supporting footcomprises a linear bar which extends parallel to said three parallelcross bars.
 12. The unitary wire chair of claim 8 wherein said chair isadapted to be secured onto a reinforcement element by locating thereinforcement element between two of said three parallel cross bars andthen rotating said chair 90° to lock said chair onto said reinforcementelement.
 13. The unitary wire chair of claim 8 wherein said chair issubjected to heat treatment after formation of said chair.
 14. Theunitary wire chair of claim 13 wherein said heat treatment comprisesheating said chair to a temperature of between 450° to 550° F. and thencooling said chair to impart improved form stability to said chair. 15.A unitary wire chair for supporting a concrete reinforcing element abovea supporting surface, which chair comprises: at least three parallelcross bars connected by at least two connecting bars, at least one ofsaid parallel cross bars being adapted to be received atop a reinforcingelement and at least two parallel cross bars being adapted to bereceived on the underside of said reinforcing element; and riser barsextending downwardly away from an end of at least two of said parallelcross bars.
 16. The unitary wire chair of claim 15 wherein each of saidriser bars is connected at its lower end to a supporting foot.
 17. Theunitary wire chair of claim 16 wherein each supporting foot comprises alinear bar which extends parallel to said three parallel cross bars. 18.A unitary wire chair for supporting concrete reinforcing element above asupporting surface while concrete is poured onto that supportingsurface, which chair comprises: at least three parallel cross barsconnected by two connecting bars, a central one of said three parallelcross bars being adapted to be received atop a concrete reinforcingelement and the other two of said three parallel cross bars beingadapted to be received on the underside of said concrete reinforcingelement, said two connecting bars being connected to opposite ends ofsaid central one of said three parallel cross bars; and a pair of riserbars extending downwardly away from an end of each of said other twoparallel cross bars.
 19. The unitary wire chair of claim 18 wherein eachof said riser bars is connected at its lower end to a supporting foot.20. A unitary wire chair for supporting concrete reinforcing rebar orthe like above a supporting surface while concrete is poured onto thatsupporting surface, which chair comprises: at least three parallel crossbars connected by two connecting bars, said two connecting bars beingconnected to opposite ends of a central one of said three parallel crossbars; and a riser bar extending downwardly away from an end of each ofsaid other two parallel cross bars.
 21. The unitary wire chair of claim20 wherein each of said riser bars is connected at its lower end to asupporting foot.
 22. The unitary wire chair of claim 21 wherein eachsupporting foot comprises a linear bar which extends parallel to saidthree parallel cross bars.
 23. The unitary wire chair of claim 21wherein said chair is adapted to be secured onto a rebar or the like bylocating the rebar between two of said three parallel cross bars andthen rotating said chair 90° to lock said chair onto said rebar or thelike.
 24. A unitary wire chair for supporting concrete reinforcing rebaror the like above a supporting surface, which chair comprises: a centralsection of said wire having generally U-shaped loops formed at itsopposite ends, each of said loops terminating in a generally verticallyextending riser bar; and a supporting foot formed on an end of eachriser bar.
 25. The unitary wire chair of claim 24 wherein said centralsection of wire is a straight linear section of wire.
 26. The unitarywire chair of claim 24 wherein said central section of wire is generallyV-shaped.
 27. A unitary wire chair for supporting concrete reinforcingrebar or the like above a supporting surface, which chair comprises: alower central foot supporting section; riser bars extending upwardlyfrom said lower central foot section; generally U-shaped loops formed onthe upper ends of each of said riser bars, said loops being adapted tobe snap-fit onto a rebar or other type of concrete reinforcing wire orrod.
 28. A unitary wire chair for supporting concrete reinforcing rebaror the like, said chair being formed from a single length of wire havingat least one portion of the wire so configured that it may be snap-fitonto a rebar or the like and retained thereon without any otherattachment device.
 29. The unitary wire chair of claim 28 wherein saidchair comprises riser bars which support said snap-fit portion spacedfrom at least one supporting foot portion of said chair.